Misconceptions on how to expose for digital.

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Dmitry Kitsov

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Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 5:40 am

There seems to be a persistent misconception among many of the people on how to expose digital capture and specifically raw digital capture. It is understandable that a knee jerk reaction of any novice (and some of us who come from a wedding videos and ENG background) is to expose so the picture looks "good" on the monitor. This of course ignores the fact that BMCC is a camera created with the post production in mind. One must shoot for the maximum data, not for the middle gray to fall into zone V.
Interestingly enough the concept does not seem to be of difficult one to explain to people who have somewhat of an advanced black and white film experience. When discussing this topic with people who are familiar with the zone system and with how one exposes and then develops b&w film for the maximum detail retention (expose for darks develop for the highlights, which is of course an opposite for digital), and then prints it for maximum image impact, there is no issue in understanding this.
Please expose to the right (use zebras) and then grade. Shooting raw (or even anything else digitally) is benefited greatly by this approach. You colorist will thank you.
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Remo Pini

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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 8:10 am

I guess the problem comes from people sharing their vast experience using previous systems. Not taking into account, that all these recipes and procedures that worked very well in the past are slowly being replaced by "something new" (and for which that experience pool doesn't fully exist yet).

We'll get there collectively :)
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Frank Glencairn

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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 9:56 am

Yeah, I have a ton of requests regarding exposure, since the BMC starts getting delivered.

And I totally agree, there is so much misconception out there. Took me a while to re-learn my exposure tactics for the BMC. But actually it is idiot proof, especially in raw. Never had a camera before, that was so easy to set exposure.

When I have some time on my hands, I gonna write an article about that for my blog.

Till than, basically what Dmitry said. ETTR and make sure your 100% zebra doesn't show up.

Frank
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Set your zebras to 100%, ETTR and you're golden - and NO, you can't use TB as output for an external monitor, and you can't download the footy via TB ether.
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John Richard

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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 1:43 pm

Frank's comments are exactly spot on for me ....
In Raw, set the zebras to 100 percent. Rig your depth of field as desired and try to get your zebras to just start to appear in the highlights.
Then in Resolve you see all the wonder of the full latitude of this beauty.

It is the opposite of film for me - you concentrate on the highlights as your base of exposure judgement; not the blacks.

Always amazed at sky shots - sky seems blown out until you start dialing back in Resolve and suddenly all the blue and cloud detail zip right back like ... well black magic. ;>/

BMCC, Raw, Resolve - all earn the company its name.
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Nick Smith

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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 1:47 pm

Does the prores codec hold enough information for that kind of exposure as well?
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Brad Ballew

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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 2:02 pm

Should we be making blanket statements about exposure for all situations? I understand why ETTR is being preached for the BMCC, but is it the right approach for even something like narrative filmmaking? My day to day job is News and I use my BMCC exactly how many suggest we use it. I adjust until there are no zebras or just zebras in acceptable areas. However, I am planning on shooting a short or two later this year and I am not so sure ETTR is the best approach.

This is a situation I am sure could benefit from a more traditional approach. Of course it all depends on what look you want and how much work you want to put into DI. However, when you alter the image a lot in post it does tend to change the aesthetic some. Depending on what your project is, that could be a good thing or a bad thing.

When it comes to film I like the most natural look possible. One of my favorite DPs is Roger Deakins. That's probably not surprising since he seems to be pretty popular with wannabe filmmakers. I love how natural his images look and at no point do I ever get distracted by his lighting. I think a lot of the reason is that he takes a pretty minimalistic approach to his cinematography. About the only filter he ever uses is an ND, I found out just the other day from him that he uses primarily practicals even on Skyfall, (the day he told me this, the only film lights he had used all day were two 1K Fresnals which he says is "quite normal for him".) He also lights and exposes like he would a traditional film and does very little in the DI suite. About the only thing he does in post is apply whatever LUT he has for that particular film.

I am not trying to say anybody is right or wrong, or that Deakins is God and we should all do it like him. But it goes to show that there isn't a single right approach. I will always ETTR for my job because it works and it's easy. However, I will probably take Deakin's approach when I shoot my film because that is the kind of look I like.

EDIT: Here was what he had to say about Shooting for Information VS. Traditional Shooting in case anyone is interested.

Shooting for information? Just as you can't just 'cover' a scene from multiple camera angles and 'make it in the cutting room', you can't create a 'look' after the fact .... unless you want your resulting film to be and look like animation. As I have said countless times, I like to shoot what is in my minds eye in camera. I know some find the results 'acceptable' through manipulating the image in post but you can't change perspective nor can you truly 'light' a scene in a DI suite.
That said, a 'camera' can now 'capture' a set and a performance in three dimensions. It is possible to choose a shot after the fact, light the scene after the fact, create the players after the fact. If that's your preference all you need is money.
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Frank Glencairn

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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 3:34 pm

brad12d3 wrote:This is a situation I am sure could benefit from a more traditional approach.


What makes you sure, that not giving the sensor as much light as possible could be a benefit?
(Unless you love noisy shadows).

When you record audio, are you recording at -50 ?
No, you would never do that. You would probably fire a sound guy, that comes up with that idea.
You want to be as close as possible to -12, to get the cleanest possible Audio recording.
And you know, you can always lower your audio levels in post without damage, if they are too loud.

Same with the BMC - especially in raw.

You have to relearn the way you think about exposure.
While shooting, it's all about getting your ratios right and saturating the sensor as much as possible.
The "dialing in your shot" you are used to from other systems, comes in post.
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Set your zebras to 100%, ETTR and you're golden - and NO, you can't use TB as output for an external monitor, and you can't download the footy via TB ether.
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 3:59 pm

Nick Smith wrote:Does the prores codec hold enough information for that kind of exposure as well?


It holds a fair amount of data. From my understanding it takes the 12bit data and remaps it to 10bit with white balance burnt in. There is still loads of info in the ProRes file. More than enough to make white balance adjustments and to grade.
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 4:51 pm

brad12d3 wrote:Should we be making blanket statements about exposure for all situations? I understand why ETTR is being preached for the BMCC, but is it the right approach for even something like narrative filmmaking? My day to day job is News and I use my BMCC exactly how many suggest we use it. I adjust until there are no zebras or just zebras in acceptable areas. However, I am planning on shooting a short or two later this year and I am not so sure ETTR is the best approach.

This is a situation I am sure could benefit from a more traditional approach. Of course it all depends on what look you want and how much work you want to put into DI. However, when you alter the image a lot in post it does tend to change the aesthetic some. Depending on what your project is, that could be a good thing or a bad thing.

When it comes to film I like the most natural look possible. One of my favorite DPs is Roger Deakins. That's probably not surprising since he seems to be pretty popular with wannabe filmmakers. I love how natural his images look and at no point do I ever get distracted by his lighting. I think a lot of the reason is that he takes a pretty minimalistic approach to his cinematography. About the only filter he ever uses is an ND, I found out just the other day from him that he uses primarily practicals even on Skyfall, (the day he told me this, the only film lights he had used all day were two 1K Fresnals which he says is "quite normal for him".) He also lights and exposes like he would a traditional film and does very little in the DI suite. About the only thing he does in post is apply whatever LUT he has for that particular film.

I am not trying to say anybody is right or wrong, or that Deakins is God and we should all do it like him. But it goes to show that there isn't a single right approach. I will always ETTR for my job because it works and it's easy. However, I will probably take Deakin's approach when I shoot my film because that is the kind of look I like.

EDIT: Here was what he had to say about Shooting for Information VS. Traditional Shooting in case anyone is interested.

Shooting for information? Just as you can't just 'cover' a scene from multiple camera angles and 'make it in the cutting room', you can't create a 'look' after the fact .... unless you want your resulting film to be and look like animation. As I have said countless times, I like to shoot what is in my minds eye in camera. I know some find the results 'acceptable' through manipulating the image in post but you can't change perspective nor can you truly 'light' a scene in a DI suite.
That said, a 'camera' can now 'capture' a set and a performance in three dimensions. It is possible to choose a shot after the fact, light the scene after the fact, create the players after the fact. If that's your preference all you need is money.


Roger Deakins on not using (oh that's right USING postproduction):
Skyfall was no exception. “Sometimes Sam would be watching another monitor and he would make a comment,” Deakins says. “I’d take him over to the DIT’s station and say, ‘That is what the camera is seeing, and I can change it here or in post.’ I think that was very advantageous, and also I think it was nice for Sam...



Oh and by the way, exposing to the right does not change anything about the way you light. The only thing that is changed is how many bits will be allotted to your actual image (or rather to the range of the image with the meaningful information). This happens due to the linear nature if the sensor. Yet again there seems to be a confusion about lighting exposure (ratios of lights etc) and the exposure needed to allow sensor capture an image.
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 6:14 pm

adamroberts wrote:
Nick Smith wrote:Does the prores codec hold enough information for that kind of exposure as well?


It holds a fair amount of data. From my understanding it takes the 12bit data and remaps it to 10bit with white balance burnt in. There is still loads of info in the ProRes file. More than enough to make white balance adjustments and to grade.


If you are recording ProRes in camera, internally I think it likely that the BMCC is working with at least 16bit data from the sensor and remapping that via their ProRes Film or ProRes Video curves to 10bit. Their intermediate calculations could well be using 32bits as does Resolve. They wouldn't be starting from the raw 12bit data, which is also derived from at least 16bit sensor data, to derive the 10bit ProRes.

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Brad Ballew

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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 6:15 pm

Roger Deakins on not using (oh that's right USING postproduction):
Skyfall was no exception. “Sometimes Sam would be watching another monitor and he would make a comment,” Deakins says. “I’d take him over to the DIT’s station and say, ‘That is what the camera is seeing, and I can change it here or in post.’ I think that was very advantageous, and also I think it was nice for Sam...



Oh and by the way, exposing to the right does not change anything about the way you light. The only thing that is changed is how many bits will be allotted to your actual image (or rather to the range of the image with the meaningful information). This happens due to the linear nature if the sensor. Yet again there seems to be a confusion about lighting exposure (ratios of lights etc) and the exposure needed to allow sensor capture an image.


I am not trying to imply that Deakins didn't believe in using the tools available in post production or that it was somehow bad. However, the explanations when it comes to exposure have seemed a bit simplistic and pair that with recommendations I have seen from users that the use of light meter is unnecessary and it can become easy to send the wrong message to people who are still learning the craft.

Proper lighting isn't as simple as dial it down until you don't see zebras. I had a shot of a grassy field that I did that with and the exposure for the grass was very high in the curve. When I brought it down in post something seemed a bit off about it. Could have been my imagination maybe, but it made me wonder should we ever consider exposure that simple? Just dial it down until your just under zebras?

I am not saying that exposing to the right is necessarily wrong but I think it's important that we elaborate on that some. Should I really let important parts of my scene get up in the high 90s? If the brightest part of the image is the most important should I take it that high when exposing? Or should it fall more around in the 80s?

Also, why in the world would we tell someone not to get a light meter because we are shooting RAW? It's seems kind of a silly suggestion considering that this is a cinema camera. I just got my first light meter today and already I feel as though I am better understanding how light falls around a room. Just the few hours I have used it have been very enlightening. I feel like it will ultimately help me become a better cinematographer.

I don't think anyone intends to over simplify lighting and teach bad practices to up and comers but there are a lot of people who might take things the wrong way and decide that instead of proper lighting they just need to expose to the right and "light it in post" using mask in Resolve. The truth is that a manipulation in post isn't the same as an artistically lit set. It will look different. I think Deakins likes that he has the flexibility in post, but unless the film calls for a lot of manipulation (i.e. Oh Brother Where Art Thou?) he prefers to keep things simple. He has been very clear on this point. He has said time and time again that what he gets in camera is very similar to what you ultimately see in the theater. Of course he does add a LUT, but there isn't too much more than that done to his films.

If I light and expose my film in a traditional way without ETTR and keep my post work minimal (adding a lut) is my image going to come out all noisy and crappy? Or is ETTR for when you know you are going to be pushing things around a lot in post?

I think this clarifies Deakins stance on the DI suite:
understand what you are saying and I would fully embrace the 'don't touch my original' maxim if it were really practical. The speed at which most productions are forced to work these days makes the DI, for me, a great tool. As I have said many times, I do very little in the DI suite and I aim to get my 'original' as close as possible to the final result I am after but.... When a white wall is being hit by a hot sun and there is no time to flag it or wait for the light I am quite happy that I have such technology to hand.
There was a shot done on the film 'Cleopatra' for which they waited 6 months. The first time the shot was set, with the cameras ready to roll, the cinematographer realized the sun had shifted and was not hitting the set at the correct angle. 6 months later it was again in the perfect place. I wish I had that kind of control!
Last edited by Brad Ballew on Sat Mar 30, 2013 6:42 pm, edited 1 time in total.
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 6:39 pm

Brad Ballew wrote:Should we be making blanket statements about exposure for all situations?...

I am not trying to say anybody is right or wrong, or that Deakins is God and we should all do it like him. But it goes to show that there isn't a single right approach. I will always ETTR for my job because it works and it's easy. However, I will probably take Deakin's approach when I shoot my film because that is the kind of look I like.

EDIT: Here was what he had to say about Shooting for Information VS. Traditional Shooting in case anyone is interested.

Shooting for information? Just as you can't just 'cover' a scene from multiple camera angles and 'make it in the cutting room', you can't create a 'look' after the fact .... unless you want your resulting film to be and look like animation. As I have said countless times, I like to shoot what is in my minds eye in camera. I know some find the results 'acceptable' through manipulating the image in post but you can't change perspective nor can you truly 'light' a scene in a DI suite.


I am sure there are situations when exposing to the (extreme) right is not a necessity. For example since raw is applying a log curve to linear exposure information coming from the sensor, if your scene and your complete focus of attention is on very bright things, as in a shot of downhill skiing perhaps, I think you could experiment and find you capture better overall image details backing off 95% zebras rather than 100% zebras. Definitely something to learn by experience when it's appropriate to bend the ETTR a little. But for general scenes that won't strain the dynamic range of the sensor, it may be best in nearly all situations to follow the rule. What it buys you is simply reduced noise in the shadows and that's a great place to begin regardless of your final deliverable's appearance.

Apologies for the arrogance of my ignorance, but it seems to that Deakins will one day amend or update his statement that you quoted because he frankly sounds like he has two feet firmly planted in the film world and only one eye on digital. If you think about it, he is speaking cavalierly from his position of esteem and authority.

When he gives it some time to digest, he's going to clarify what he meant. Nothing he says actually contradicts the ETTR guidance, as he is right that he shoots what is in his mind's eye and he has a look he knows he wants before he shoots. That's all good stuff that everyone should follow when composing and lighting, but it doesn't mean the image displayed on the back of the BMCC must look like his final deliverable, does it? If he uses a monitor on set, he can shoot ETTR and likely get close to the look he wants via a LUT on his external monitor and perhaps that is all he meant to say in the first place.

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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 6:51 pm

Just don't confuse "exposure" with "lighting". They are two different beasts of which one relies on the other. One is more technical, the other is more art.

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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 7:10 pm

MichaelP wrote:Just don't confuse "exposure" with "lighting". They are two different beasts of which one relies on the other. One is more technical, the other is more art.

Michael


I do understand the difference as it is a pretty simple concept. :) I guess what all my rambling boils down to is A.) Is ETTR using 100 zebras good for every situation? What if the most important part of the image hits the scale at 98? Do we really want that?

Also, is the concept behind ETTR just a safeguard for someone who is going to do a lot of manipulation in post? What if I have no intention of lifting my shadows? If I light a scene like I want to see it and expose like I would for film and the most manipulation I do is add a LUT,.. is my image somehow going to come out a mess with tons of noise?

Also, I think its good to understand that manipulating in Resolve is not the same as lighting a set. The more you push things around, the more it changes the aesthetic. Depending on how you manipulate it and how much you push it can make it look a bit more artificial. I think that is what Deakins was referring to in the first quote I posted.

Perhaps it is best to say that it's safer to over expose a little to avoid noise in the shadows, but you might not want the important parts at the very top of the curve. Would that be accurate?
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 7:22 pm

Brad Ballew wrote:Is ETTR using 100 zebras good for every situation? What if the most important part of the image hits the scale at 98? Do we really want that?

Perhaps... you might not want the important parts at the very top of the curve. Would that be accurate?


That is what I was referring to in the example of shooting downhill skiing on a bright day. There may be exceptional times when you back off the zebras a little more than in your general situation because you want to concentrate on items that are very near to the maximum light values, but in your general situation, no, go with ETTR and enjoy the maximum possible dynamic range in your digital negatives regardless of how you make your prints.

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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 8:20 pm

Brad Ballew wrote:[ What if I have no intention of lifting my shadows? If I light a scene like I want to see it and expose like I would for film and the most manipulation I do is add a LUT,.. is my image somehow going to come out a mess with tons of noise?


Not giving the sensor as much light as possible, means you are giving away dynamic range.
And yeah, that can backlash in some situations, if you slap an LUT on the material.

Plus/minus 5 IRE in raw, probably don't make a huge difference in most situations though.

I was just shooting for 3 weeks in Canada BC - nothing but snow. As Rick said, this is an exception, where you back up a hair or two. But even there, when I would have exposed more conservative, I would not have been able to recover any detail in the dark trees.
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Set your zebras to 100%, ETTR and you're golden - and NO, you can't use TB as output for an external monitor, and you can't download the footy via TB ether.
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 9:16 pm

If I have a close up on an actors face is it safe taking the exposure of the skin to the high 90s just before I would get zebras?
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 9:22 pm

I just found out something important!

I tested daylight vs. tungsten. The zebras are not accurate with tungsten. I had no 100% zebras and my red channel was clipped pretty bad. With daylight it´s no problem but beware when you are under tungsten! Maybe set zebras to 90 then.

Edit: also colours look much better with daylight. This camera doesn´t seem to like tungsten.
Last edited by Felix Steinhardt on Sat Mar 30, 2013 9:40 pm, edited 1 time in total.
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 9:37 pm

Felix Steinhardt wrote:I just found out something important!

I tested daylight vs. tungsten. The zebras are not accurate with tungsten. I had no 100% zebras and my red channel was clipped pretty bad. With daylight it´s no problem but beware when you are under tungsten! Maybe set zebras to 90 then.


So I wonder if a good piece of info would be at what point does the shadows start getting an unacceptable level of noise. If there are issues with color channels clipping under tungsten then it might not be a bad idea to consider what dark areas you want to be able to see in and adjust lighting and/or set exposure so that they are above this acceptable level. Perhaps in certain circumstances this would be a good approach as opposed to pushing the image so far right. If the red channel clips under tungsten then you certainly wouldn't want to push a close up shot of someone's face to just under 100 zebras.
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 9:42 pm

I think the point of rules (like ETTR, Zebra 100%) is covered by the old 80/20 adage... it works in 80% of the cases, so it's good for most in most cases.

People should never judge a rule by the extremes, because at that point, ALL rules break down or fail partially and experience has to take over.

Ultimately, the only rule is that there are no rules that always work. If you shoot it and the end result looks good, you did good, otherwise, you screwed up (whether done in post or in camera is really completely irrelevant).
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 10:19 pm

remopini wrote:I think the point of rules (like ETTR, Zebra 100%) is covered by the old 80/20 adage... it works in 80% of the cases, so it's good for most in most cases.

People should never judge a rule by the extremes, because at that point, ALL rules break down or fail partially and experience has to take over.

Ultimately, the only rule is that there are no rules that always work. If you shoot it and the end result looks good, you did good, otherwise, you screwed up (whether done in post or in camera is really completely irrelevant).


That's the point I was trying to make. I will probably always use the ETTR rule (perhaps with zebras at 90-95) when doing my ENG stuff. However, when making my films I think it's best that I take a bit more thoughtful approach. I would hate to have spent all this time shooting something only to find out that I had color channels clipping the whole time because of how the camera was responding to the particular lights being used (i.e Tungsten) My point is that this is a cinema camera and getting a good image is never so simple. Trying to make simple rules can get us in trouble. Something may work 80 percent of the time, but that's not much comfort when that really important shot falls in the 20 percent and gets screwed.

If your afraid of noise in shadows then decide before hand what you want to be able to see and adjust lighting and exposure accordingly to keep those areas above the border of acceptable noise. The thing is that most of the people on this forum can use the ETTR rule responsibly because they know their craft and will make adjustments to the rule from their own experience. An up and comer will look at it as... just over expose everything until just before 100 and create my look in post. It might work for him a lot of the time, but then it might really screw him too.
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 10:23 pm

Brad Ballew wrote:If I have a close up on an actors face is it safe taking the exposure of the skin to the high 90s just before I would get zebras?


The "skin" of a single face can have a range of several stops, depending on lighting style and scene.
But If you take the brightest point of the face into the 90s and the rest of your ratios in the scene is also fine, absolutely.

And yeah, what Felix said - single channels can clip, before showing up in the zebra, for tungsten a IR filter helps to some degree, since it is the near infrared that goes over board first. It's better to gel your lights though.
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Set your zebras to 100%, ETTR and you're golden - and NO, you can't use TB as output for an external monitor, and you can't download the footy via TB ether.
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Re: Misconceptions on how to expose for digital.

PostSat Mar 30, 2013 10:40 pm

Shooting faces I'm used to shooting 70-75% zebras.. (at least when using ENG cameras) I would guess it wouldn't be too different on the BMCC when shooting ProRes
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Re: Misconceptions on how to expose for digital.

PostSun Mar 31, 2013 3:11 am

Bill Rich wrote:Shooting faces I'm used to shooting 70-75% zebras.. (at least when using ENG cameras) I would guess it wouldn't be too different on the BMCC when shooting ProRes


The BMCC can set zebras down to 75% but what is correct for the brightest part of the face depends on the results you want to see in your brightest highlights and your shadows. It would vary depending upon the light in your scene and your goals, but I don't think you would need to set zebras so low. If your faces are much darker than the general scene highlights, it may not make any sense to set zebras for the facial highlight.

If your faces are close to the brightest part of the scene that you wish to protect, then the zebras might be at 90% or 95% or even 100%. You would know best looking at the light levels in your scene. But as John has pointed out, you are likely losing some of the dynamic range if you set zebras under 100% as you would if you are setting zebras on your faces unless the sun reflecting off a forehead is the brightest element in the scene of course. Let us know when you do your tests.

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Re: Misconceptions on how to expose for digital.

PostSun Mar 31, 2013 5:22 am

Frank Glencairn wrote:
Brad Ballew wrote:If I have a close up on an actors face is it safe taking the exposure of the skin to the high 90s just before I would get zebras?


The "skin" of a single face can have a range of several stops, depending on lighting style and scene.
But If you take the brightest point of the face into the 90s and the rest of your ratios in the scene is also fine, absolutely.

And yeah, what Felix said - single channels can clip, before showing up in the zebra, for tungsten a IR filter helps to some degree, since it is the near infrared that goes over board first. It's better to gel your lights though.


Good to know. Thanks.
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Re: Misconceptions on how to expose for digital.

PostSun Mar 31, 2013 2:33 pm

reckon we need a tutorial on how to ETTR on the BMCC. I'm confused as hell. I'm not a cameraman, just an editor interested in camerawork.

Question
1) what if I'm on f4 on my lens and ISO 800 on the camera and I 'm not hitting the 100% zebra.
The false colour in my monitor indicates skintone sitting around 70-75%. There are nothing in the scene that is brighter than the skintone. Should I then open up my iris or increase the ISO further to push up the skintone closer to 100 percent?

2) How to ETTR in night scene?
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Re: Misconceptions on how to expose for digital.

PostSun Mar 31, 2013 2:41 pm

It all depends on the situation.

You will run into a situation where - even wide open on f1.4 glass - no zebra shows up at all.

If you are on a set - bring in more light.

If you are on a beach on a cloudy dark afternoon, pulling a one-man-band shoot, all you can do, is use what's there.
http://frankglencairn.wordpress.com/

Set your zebras to 100%, ETTR and you're golden - and NO, you can't use TB as output for an external monitor, and you can't download the footy via TB ether.
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Re: Misconceptions on how to expose for digital.

PostSun Mar 31, 2013 5:01 pm

Brad Ballew wrote: I would hate to have spent all this time shooting something only to find out that I had color channels clipping the whole time because of how the camera was responding to the particular lights being used (i.e Tungsten)


That's why I would want to have a monitor that shows me RGB waveforms to be able to quickly check for clipping and usage of the full latitude of the signal.
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Re: Misconceptions on how to expose for digital.

PostSun Mar 31, 2013 5:48 pm

remopini wrote:
Brad Ballew wrote: I would hate to have spent all this time shooting something only to find out that I had color channels clipping the whole time because of how the camera was responding to the particular lights being used (i.e Tungsten)


That's why I would want to have a monitor that shows me RGB waveforms to be able to quickly check for clipping and usage of the full latitude of the signal.



That's a good point. I hope you guys don't mind me challenging ideas.. I just like to be sure. I am convinced that ETTR is the best approach to this camera but at the same time it's important for people to understand the tools and how they work. I am still learning myself and part of the reason I make challenging statements is that I want to be thorough.

I think it's important to read a lot of what people have to say and then just go shoot and experiment and ultimately decide what works best for you.
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Re: Misconceptions on how to expose for digital.

PostSun Mar 31, 2013 6:34 pm

i was under the impression that you shot negative film with at least 1 stop open then key normaly to get the shadows more exposed. Thats at least what they tought us here at school in poland?

I myself tried to shoot as said with ETTR (100 zebra just barely showing if nothing at all) outside yesterday and we got realy good results by checking single frames.

we had this one shot where this one ice fisher was on the lake and i exposed like said over, and the whole screen was white with nothing on it, as if over exposed (video display was on, not film), but when we pulled down in photoshop the exposure, holy jesus what happened... Everything was there (ofcourse he was realy far away, and i botched the focus much (canon 70-300mm 3,5 to 5,6fstops)
My settings were 5600k, 800ISO, 18o degree, 5 ,6 stops, no ND (only the anti-polarizing filtr on), RAW, max 300mm used (going above 600mm on the bmcc)...

We were just purely amazed :<
Will give some samples later this week.
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Re: Misconceptions on how to expose for digital.

PostTue Apr 02, 2013 7:35 pm

Did anyone test if you can ETTR in ProRes mode and bring back all the information in post?
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Re: Misconceptions on how to expose for digital.

PostTue Apr 02, 2013 8:07 pm

florianblang.com wrote:Did anyone test if you can ETTR in ProRes mode and bring back all the information in post?


No need to "bring back all the information in post".

If you set your zebras to 100% and expose your scene so no zebras show (or only show on elements you don't mind clipping, like the sun or lights in the scene) the BMCC then takes the RAW sensor data and maps it to the 10bit ProRes file, applying the chosen LUT (film or video) and exposure curve for the ISO.

You ProRes file is then correctly exposed.

It really is that simple.
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Re: Misconceptions on how to expose for digital.

PostTue Apr 02, 2013 8:41 pm

adamroberts wrote:
florianblang.com wrote:Did anyone test if you can ETTR in ProRes mode and bring back all the information in post?


No need to "bring back all the information in post".

If you set your zebras to 100% and expose your scene so no zebras show (or only show on elements you don't mind clipping, like the sun or lights in the scene) the BMCC then takes the RAW sensor data and maps it to the 10bit ProRes file, applying the chosen LUT (film or video) and exposure curve for the ISO.

You ProRes file is then correctly exposed.

It really is that simple.


Thanks! Can´t wait to shoot this weekend the first time with it :D
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Re: Misconceptions on how to expose for digital.

PostWed Apr 03, 2013 4:34 am

Few of us have used a camera with this lattitude before that records in raw log format. Bear in mind that the camera (according to JB) actually records 16 bits of linear data, then compresses that into 12 bit log data per pixel. The 16 bits is not real pure data, for sure, but the point is that this camera captures a big range, AND STORES IT (in RAW). That is what we want. But when you look at the 8-bit linear view on the camera screen, for example, the natural tendency is to expose to make that image look about right. That is not correct, because the LUT being used is not usually right for the scene. So even though it 'seems wrong' to expose based on the zebra formula, when you look at your result in Resolve and see what you really have, all of that seemingly washed-out stuff comes out looking gorgeous after grading. You can overdo it, as Hurlbut did on his first try, and as most of us probably have on occasion, but the ETTR rule based on the high zebra works very well in RAW on the BMCC.

Roger Deakins is a very good cinematographer. Even though he does not do grading, he knows what his LUTs look like, and he has plenty of experience with various cameras, including seeing what comes out in the final grade. Like every other cinematographer, his primary job is lighting. He is determining the look of each shot via control of light. He is accustomed to big crews to accomplish this. Even though some 'lighting' can now be done in post better than we ever thought before, using high DR images and tools like Resolve, we all know you cannot light in post like you light on set. Who is going to put a rim light on an actor's face in post? The real control of light is still on the set. The big deal is that a high DR image capture plus a tool like Resolve allows you to 'get away with' more on set, and it allows you to really dial things in very nicely in post. Whenever I watch some of these 'making of' videos that are included with modern movie blu-rays, they often show minimally graded shots from the main cameras. I am always amazed at the difference between these shots and the fully graded shots in the final release.

So we are marching into a brave new world where ordinary shooters can do grading using high end tools like Resolve. That is what BMD has enabled. Heck, you can even create artificial tracked super-shallow DOF using Resolve! So we have to learn how to drive the fancy new car, because it is way fancy!
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Re: Misconceptions on how to expose for digital.

PostWed Apr 03, 2013 7:53 am

DNomer wrote:Few of us have used a camera with this lattitude before that records in raw log format. Bear in mind that the camera (according to JB) actually records 16 bits of linear data, then compresses that into 12 bit log data per pixel. The 16 bits is not real pure data, for sure, but the point is that this camera captures a big range, AND STORES IT (in RAW). That is what we want. But when you look at the 8-bit linear view on the camera screen, for example, the natural tendency is to expose to make that image look about right. That is not correct, because the LUT being used is not usually right for the scene. So even though it 'seems wrong' to expose based on the zebra formula, when you look at your result in Resolve and see what you really have, all of that seemingly washed-out stuff comes out looking gorgeous after grading. You can overdo it, as Hurlbut did on his first try, and as most of us probably have on occasion, but the ETTR rule based on the high zebra works very well in RAW on the BMCC.

Roger Deakins is a very good cinematographer. Even though he does not do grading, he knows what his LUTs look like, and he has plenty of experience with various cameras, including seeing what comes out in the final grade. Like every other cinematographer, his primary job is lighting. He is determining the look of each shot via control of light. He is accustomed to big crews to accomplish this. Even though some 'lighting' can now be done in post better than we ever thought before, using high DR images and tools like Resolve, we all know you cannot light in post like you light on set. Who is going to put a rim light on an actor's face in post? The real control of light is still on the set. The big deal is that a high DR image capture plus a tool like Resolve allows you to 'get away with' more on set, and it allows you to really dial things in very nicely in post. Whenever I watch some of these 'making of' videos that are included with modern movie blu-rays, they often show minimally graded shots from the main cameras. I am always amazed at the difference between these shots and the fully graded shots in the final release.

So we are marching into a brave new world where ordinary shooters can do grading using high end tools like Resolve. That is what BMD has enabled. Heck, you can even create artificial tracked super-shallow DOF using Resolve! So we have to learn how to drive the fancy new car, because it is way fancy!


I Just use the KISS method with the BMD and my own experience,
then compare it with others to see if I'm doing it right.

There is "NO" right or wrong "way" as far as color grading, but this camera does have
it's Exposure preference to ETTR that allows you more latitude in the grade to play in the YRGB color space and get the most out of your Color Grade, This alone is why you should learn how to color correct and use a professional calibrated monitor with software such as Davinci Resolve.
If you are new to color grading and or have no experience, then I highly suggest you get some
experience in resolve or you may find your $3000 BMCC investment a disappointment.

And lets not forget the hardware it takes to deal with the RAW files.
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Re: Misconceptions on how to expose for digital.

PostTue May 14, 2013 11:58 am

florianblang.com wrote:Did anyone test if you can ETTR in ProRes mode and bring back all the information in post?


If you shoot ProRes in film mode you can bring back more highlight detail in post than you are seeing on the Rec.709 monitoring. You can do this in Resolve, or for example use the exposure slider I have built into my FCP X plugin (beta now, but hopefully due for release soon). You can see this demonstrated in my video here:

http://bit.ly/12tUSs2

This will let you ETTR when shooting ProRes film mode, which may result in an excessively bright image with the default LUT, but when you drop the exposure in post to the desired value, you crush down any shadow noise.
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Re: Misconceptions on how to expose for digital.

PostTue May 14, 2013 9:17 pm

Nick Shaw wrote:
florianblang.com wrote:Did anyone test if you can ETTR in ProRes mode and bring back all the information in post?


...This will let you ETTR when shooting ProRes film mode, which may result in an excessively bright image with the default LUT, but when you drop the exposure in post to the desired value, you crush down any shadow noise.


Nick, John Brawley has recently recommended backing off a little from full ETTR with 100% zebras if shooting ProRes. Yes, backing off a little may decrease the latitude a little but it will offer some additional protection of the highlights. John didn't say exactly what to do as I think it might depend on the scene and lighting, but perhaps generally setting zebras at 95% would be safer when shooting ProRes.

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Re: Misconceptions on how to expose for digital.

PostWed May 15, 2013 8:50 pm

rick.lang wrote:…perhaps generally setting zebras at 95% would be safer when shooting ProRes.


This is speculation on my part, as I don't have a camera to test, but I suspect the reason for backing off a bit may be because even if nothing is clipping in the RAW, the channel gains used to bake in the white balance to the ProRes could cause one or more channels to clip.
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Re: Misconceptions on how to expose for digital.

PostWed May 15, 2013 9:16 pm

Yup, even in raw mode, a single channel can clip before the zebra comes even on.
http://frankglencairn.wordpress.com/

Set your zebras to 100%, ETTR and you're golden - and NO, you can't use TB as output for an external monitor, and you can't download the footy via TB ether.
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Re: Misconceptions on how to expose for digital.

PostWed May 15, 2013 9:26 pm

Dmitry Kitsov wrote:There seems to be a persistent misconception among many of the people on how to expose digital capture and specifically raw digital capture. It is understandable that a knee jerk reaction of any novice (and some of us who come from a wedding videos and ENG background) is to expose so the picture looks "good" on the monitor. This of course ignores the fact that BMCC is a camera created with the post production in mind. One must shoot for the maximum data, not for the middle gray to fall into zone V.
Interestingly enough the concept does not seem to be of difficult one to explain to people who have somewhat of an advanced black and white film experience. When discussing this topic with people who are familiar with the zone system and with how one exposes and then develops b&w film for the maximum detail retention (expose for darks develop for the highlights, which is of course an opposite for digital), and then prints it for maximum image impact, there is no issue in understanding this.
Please expose to the right (use zebras) and then grade. Shooting raw (or even anything else digitally) is benefited greatly by this approach. You colorist will thank you.


If we can get histograms, that can help. Zebra is one of the aides, but only shows clipping highlights. If ultrasocope can be built into the camera, can help us moving ETTR. Well,,,,plus found out the trick with compatible lenses and the IRIS button. Pretty neat.
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Re: Misconceptions on how to expose for digital.

PostSat Jun 22, 2013 7:12 am

Really old subject but i just have to share my experience.

We were out shooting music video with red.

Really young team operating all the stuff.
Not much experience with lights contrast ratios and no experience with
histograms.

I had to pull my hair and make some faces to get attention that
light levels were low and contrast levels were also bad.

All was looked at monitors god knows if and how accurate at all.

Not the case with bmc but fine example that using zebras and histogram can save
you and give you accurate readings.

I see it on daily basis when i'm grading in resolve. Your eye will lie in time
but scopes will be accurate. Same goes with over exposing.
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Re: Misconceptions on how to expose for digital.

PostSun Jun 23, 2013 6:43 am

vjone wrote:
Dmitry Kitsov wrote:There seems to be a persistent misconception among many of the people on how to expose digital capture and specifically raw digital capture. It is understandable that a knee jerk reaction of any novice (and some of us who come from a wedding videos and ENG background) is to expose so the picture looks "good" on the monitor. This of course ignores the fact that BMCC is a camera created with the post production in mind. One must shoot for the maximum data, not for the middle gray to fall into zone V.
Interestingly enough the concept does not seem to be of difficult one to explain to people who have somewhat of an advanced black and white film experience. When discussing this topic with people who are familiar with the zone system and with how one exposes and then develops b&w film for the maximum detail retention (expose for darks develop for the highlights, which is of course an opposite for digital), and then prints it for maximum image impact, there is no issue in understanding this.
Please expose to the right (use zebras) and then grade. Shooting raw (or even anything else digitally) is benefited greatly by this approach. You colorist will thank you.


If we can get histograms, that can help. Zebra is one of the aides, but only shows clipping highlights. If ultrasocope can be built into the camera, can help us moving ETTR. Well,,,,plus found out the trick with compatible lenses and the IRIS button. Pretty neat.


Agreed. Would be nice to have histogram or at least having zebras be less weighted and just come on whenever any one channel gets clipped.
Dmitry Kitsov

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